I want to generate a trigger circuit to detect that a WHEEL is stationary. The wheel has slots on its periphery.
There is a LED transmitter in front and a photodiode behind the wheel.
As the wheel rotates and the slots come in front of the LED and then pass by, there are pulses recorded by the photodiode.
When the photodiode comes to rest with the slot in front of LED, there is continuous DC signal output.
The difference between motion and stationary wheel appears as a pulse train and continuous DC respectively.
Based on this, I would appreciate your assistance to design a trigger mechanism that discriminates between pulse train and Continuous Dc and triggers only due to the continuous signal?
The pulses are about 10-20ms wide and occur every 50ms, as shown in attachment.

It means that when the output side of the receiver is Low then there is no signal from the LED transmitter, if the output side of the receiver is High then it has received the signal from the LED transmitter.

It means that when the output side of the receiver is Low then there is no signal from the LED transmitter, if the output side of the receiver is High then it has received the signal from the LED transmitter.

Click to expand...

Thanks everybody.
The wheel is similar to the optical encoder wheel.
It rotates on a shaft and has slots in it.